Corrosion inhibitor

Abstract

The corrosion inhibitor blend of at least one corrosion inhibitor base (which may be a Mannich reaction product), a solvent selected from the group consisting of C₁ acids and ester and salt derivatives thereof, and optionally a surfactant, has been found to be effective as a corrosion inhibitor for metals in acid media, particularly fluids containing halogen acids. The corrosion inhibitor has improved performance over similar or identical corrosion inhibitor compositions where an alcohol such as methanol is used as a solvent. Suitable, non-limiting possibilities for the solvent include, but are not necessarily limited to formic acid, formate salts, methyl formate, ethyl formate, benzyl formate, formate salts of amines, inorganic formate, and mixtures thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 393,465 filed Mar. 20, 2003, which in turn claims the benefit of U.S. Provisional Application No. 60 / 368,750 filed Mar. 28, 2002.TECHNICAL FIELD [0002] The invention relates to methods and compositions for inhibiting corrosion of metals, and, in one aspect, more particularly relates to methods and compositions for inhibiting corrosion of metals in acid environments where the acid contains halogen, such as hydrochloric acid, hydrofluoric acid, and the like. BACKGROUND OF THE INVENTION [0003] It is well known that steel surfaces will corrode in the presence of acid environments. While the rate at which corrosion will occur depends on a number of factors, such as the steel alloy itself, the strength and type of acid, the temperature of the environment, the length of contact, etc., some sort of corrosion invariably occurs. Alloy technology has provided materia...

AI Technical Summary

Benefits of technology

[0012] The invention also concerns methods of inhibiting the corrosion of metals in the presence of liquids containing at least one halogen acid and the corrosion inhibitor herein. The corrosion of the metal is inhibited as compared with a liquid otherwise identical but absent the corrosion inhibitor. Additionally, the methods and compositions herein include fluids for contacting metal surfaces that have had their corrosion inhibition improved by the corrosion inhibitor.

Problems solved by technology

It is well known that steel surfaces will corrode in the presence of acid environments.

Alloy technology has provided materials to withstand the incidental contact of steel with acid, but the corrosion problem is particularly aggravated when there is no choice but to contact steel with acid, as in the case of chemical processing where acids are employed.

Because of the acidic nature of the treatment fluid, the production or workover conduit which is utilized in the well in such applications encounters considerable acidic corrosion, in the forms of surface pitting, embrittlement, loss of metal component and the like.

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